This study has completed and published the second portion of a three part FDG PET study of Tourette Syndrome. We completed and analyzed an H20-15 PET activation study of developmental stuttering, which demonstrated the differences in cerebral activation patterns for speech and language. We also completed and analyzed the following H20-15 PET studies, presently being prepared for publication: a. Functional Elements of Motor Speech; b. Propositional vs. Automatic Speech; c. Prosody and Melody in Speech; d. American Sign Language vs. English; e. Male/Female Differences in Speech and Language. We are continuing an H20-15 PET activation study in Spasmodic Dysphonia, which compares task specific cerebral activity pre- and post-treatment with botulinum toxin. We are also continuing fMRI studies in language and visual perception in deaf and hearing subjects and we developed image processing and analytic techniques for functional neuroimaging studies. We derived methods to: a. determine the contribution of physiological or behavioral signals to PET images; b. segment and extract regionally defined difference scores; c. automatically extract raw values from normalized images; d. develop modified LISREL (structural equation modeling) techniques to analyze regional interrelationship in the brain.